U.S. patent number 5,550,416 [Application Number 08/386,164] was granted by the patent office on 1996-08-27 for control mechanism of revolving speed of an electric tool.
Invention is credited to We C. Fanchang, Hsueh W. Hsueh.
United States Patent |
5,550,416 |
Fanchang , et al. |
August 27, 1996 |
Control mechanism of revolving speed of an electric tool
Abstract
A control mechanism of revolving speed of an electric tool
comprises a speed changing mechanism and a speed selecting device.
The speed changing mechanism is composed of an action ring, a
locating ring and two slide rods. The control of revolving speed of
the electric tool is brought about easily and precisely by means of
the speed changing mechanism in conjunction with the speed
selecting device which is composed of a seat, a locating frame
fastened to the main body of the electric tool, and a push
button.
Inventors: |
Fanchang; We C. (Taichung,
TW), Hsueh; Hsueh W. (Taichung, TW) |
Family
ID: |
23524442 |
Appl.
No.: |
08/386,164 |
Filed: |
February 9, 1995 |
Current U.S.
Class: |
310/83; 173/216;
173/217; 310/47; 310/50 |
Current CPC
Class: |
B25F
5/001 (20130101) |
Current International
Class: |
B25F
5/00 (20060101); E21B 3/02 (20060101); E21B
3/00 (20060101); H02K 007/14 (); H02K 007/06 ();
H02K 007/10 (); E21B 003/00 () |
Field of
Search: |
;310/47,50,83
;173/216,217 ;475/297,298 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Stephan; Steven L.
Assistant Examiner: Wallace, Jr.; Michael
Attorney, Agent or Firm: Baxley, Esq.; Charles E.
Claims
What is claimed is:
1. A control mechanism of revolving speed of an electric tool
comprising a speed changing mechanism, a speed selecting device, a
gear set seat, a first gear set, a second gear set engaged with
said first gear set and, a third gear set engaged with said second
gear set, a fixing toothed sleeve including a first inner ring
teeth, and a sliding toothed ring including an outer ring teeth for
engaging with the first inner ring teeth of said fixing toothed
sleeve and including a second inner ring teeth for engaging with
said second gear set;
wherein said speed changing mechanism is composed of an action
ring, a locating ring, and two slides, said action ring being
capable of actuating said locating ring to rotate, said locating
ring provided correspondingly with two slots provided rearwardly
with slanted slots, each of said slanted slots provided
respectively at both ends thereof with a curved locating slot, said
two slide rods provided respectively with a sliding piece and a
sliding bar, said sliding bars each including a first end passing
through said gear set seat and said fixing toothed sleeve to push
said sliding toothed ring to move back and forth so as to engage
and to disengage said outer ring teeth of said sliding toothed ring
from the first inner ring teeth of said fixing toothed sleeve, said
sliding bars each including a second end slidably engaged in said
slanted slot so as to enable said sliding bar to move back and
forth and to be located in said locating slot.
2. The control mechanism of revolving speed of an electric tool as
defined in claim 1, wherein said action ring is provided with a
sector piece which is in turn provided centrally with a spring seat
for locating thereto two springs, said action ring further provided
with two protruded pieces; and wherein said locating ring is
provided with a sector seat which is of a hollow construction and
is intended to receive therein said spring seat and said springs of
said action ring in such a manner that both ends of said springs
urge respectively both side walls of said sector seat and that said
locating ring and said action ring can be actuated to turn
together, said locating ring further provided with a reinforcing
frame fastened thereto.
3. The control mechanism of revolving speed of an electric tool as
defined in claim 1, wherein said speed selecting device is capable
of actuating horizontally said action ring and said locating ring
so as to cause said sliding bar to act on said sliding toothed ring
to move back and forth; and wherein said speed selecting device is
composed of a seat, a locating frame and a push button, said seat
provided respectively at both ends thereof with a fitting hole
dimensioned to receive therein said protruded piece of said action
ring, said seat further provided centrally with a protruded seat of
a hollow construction and having a receiving slot, said locating
frame being located over said seat and fastened to a main body of
an electric tool, said locating frame provided centrally with a
long hole dimensioned to receive therein said protruded seat, said
locating frame provided correspondingly with two retaining slots,
said push button disposed in said protruded seat of said seat such
that said push button is emerged from said long hole of said
locating frame, said push button provided with two protuberances
which are located under said locating frame such that said
protuberances are exposed through said receiving slot and that said
protuberances are retained securely in said retaining slots when
said push button is moved horizontally to a left end and a right
end of said long hole.
4. The control mechanism of revolving speed of an electric tool as
defined in claim 1, wherein said gear set seat is provided
correspondingly with long slots and strip holes, in which said
sliding pieces and said sliding bars of said slide rods are
received respectively such that said sliding bars are located in
said ring slots of said sliding toothed ring via said strip holes
so as to cause said action ring to actuate said locating ring,
thereby causing said sliding toothed ring to move back and forth.
Description
FIELD OF THE INVENTION
The present invention relates generally to an electric tool, and
more particularly to a control mechanism of revolving speed of the
electric tool.
BACKGROUND OF THE INVENTION
As shown in FIG. 2, the control mechanism of revolving speed of an
electric tool is generally composed of a gear set seat 1, a gear
set A 20, a gear set B 21, a gear set C 22, a fixing toothed sleeve
28, a sliding toothed ring 24, etc. In addition, the control
mechanism is provided with a push button switch in conjunction with
a connection rod action mechanism. In operation, the push button
switch is moved back and forth so as to cause the connection rod to
actuate the sliding toothed ring 24 to move back and forth to cause
the outer ring teeth 240 to engage or disengage the ring teeth 230
located on the inner wall of the fixing toothed sleeve 23. When the
sliding toothed ring 24 is moved forward to engage the fixing
toothed sleeve 23, the gear set B 21 which is engaged with the
sliding toothed sleeve 24 is activated to reduce the revolving
speed of the hand tool. On the other hand, when the sliding toothed
ring 24 is caused to move rearwards so as to disengage the fixing
toothed sleeve 23, the sliding toothed ring 24 and the gear set B
21 are idled so that the gear set B 21 does not act to reduce the
revolving speed of the electric tool, thereby unabling the electric
tool to revolve at a high speed.
Such a control mechanism of revolving speed of the electric tool as
described above has inherently two shortcomings, which are
described hereinafter.
When an electric tool, which is operating at a high speed, is
switched to operate at a lower speed, the outer ring teeth 240 of
the sliding toothed ring 24 are not so located as to be ready to
engage the ring teeth 230 of the fixing toothed sleeve 23. As a
result, the push button switch can not be directly switched into a
low speed position. Therefore, a tool operator is required to press
continuously the push-button switch until such time when the
sliding toothed ring 24 is actuated to engage the fixing toothed
sleeve 23. It is therefore readily apparent that it is undesirable
to employ the push-button switch in conjunction with the connection
rod mechanisim. In addition, the sliding toothed ring 24 is
susceptible to tripping caused by a reaction force brought about by
the electric tool which is operated under a torsional stress that
is slightly greater than normal. Such a tripping incident of the
sliding toothed ring 24 as described above can result in the idling
of the electric tool.
SUMMARY OF THE INVENTION
It is therefore the primary objective of the present invention to
provide an improved control mechanism of revolving speed of an
electric tool, which comprises a speed changing mechanism and a
speed selecting device. The speed changing mechanism is composed of
an action ring, a locating ring and two slide rods. The control of
revolving speed of the electric tool can be brought about easily
and precisely by means of the speed changing mechanism in
conjunction with the speed selecting device.
The foregoing objective, features and advantages of the present
invention will be more readily understood upon a thoughtful
deliberation of the following detailed description of the present
invention in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a top plan view of an electric tool of the present
invention.
FIG. 2 shows a partial exploded view of the present invention.
FIG. 3 shows a sectional view of the present invention.
FIG. 4 shows a schematic view of the present invention at work.
FIG. 5 shows an exploded view of the speed selecting device of the
present invention.
FIG. 6 shows a sectional view of the speed selecting device of the
present invention.
FIG. 7 shows a schematic view of the speed selecting device at work
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, an electric tool of the present
invention is similar in construction to the prior art electric tool
and is composed of a gear set seat 1, a gear set A 20, a gear set B
21, a gear set C 22, a fixing toothed sleeve 23, and a sliding
toothed ring 24. The gear set A 20 includes a disc 201 having an
inner gear 202 engaged with a pinion 203 of an output shaft 204 and
includes three pinions 206 rotatably engaged on three projections
205 which are secured to the disc 201. The gear set B 21 includes a
disc 211 having a pinion 212 engaged with the pinions 206 and
having three pins 213 extended therefrom for rotatably supporting
three pinions 214 thereon. The gear set C 22 includes a disc 221
having a pinion 222 engaged with the pinions 214 and having three
pins 223 extended therefrom for rotatably supporting three pinions
224 thereon. The pinions 224 are provided for engaging with an
input shaft. A sliding toothed ring 24 includes an inner ring teeth
242 for engaging with the pinions 214 and includes an outer ring
teeth 240 for engaging with an inner teeth 230 of a fixing toothed
sleeve 23. The sliding toothed ring 24 is movable toward the fixing
toothed sleeve 23 so as to engage the outer ring teeth 242 with the
inner ring teeth 230 of the fixing toothed sleeve 23, and is
movable away from the fixing toothed sleeve 23 so as to disengage
the outer ring teeth 242 from the inner ring teeth 230 of the
fixing toothed sleeve 23. These component parts as mentioned above
are not the focus of the subject matter of the present invention
and will not be therefore discussed hereinafter.
The control mechanism of revolving speed of the electric tool of
the present invention comprises mainly a speed changing mechanism
and a speed selecting device. The speed changing mechanism
comprises mainly an action ring 3, a locating ring 4 and two slide
rods 5. The action ring 3 is provided with a sector piece 30 which
is in turn provided centrally with a spring seat 31 for locating
two springs 32. The action ring 3 is further provided with two
protruded pieces 33 different in shape from each other. The
locating ring 4 is provided with a sector seat 40 of a hollow
construction, in which the spring seat 31 and the two springs 32
are disposed such that the outer ends of the two springs 32 urge
two side walls of the sector seat 40, as shown in FIG. 6. As a
result, the locating ring 4 and the action ring 3 can be actuated
at the same time. The locating ring 4 is further provided
correspondingly with two slots 41 located respectively in the left
and the right sides of the frontend thereof. The slot 41 is
provided rearwards with a slanted slot 42 having respectively at
both ends thereof a curve locating slot 43. The slot 41 is provided
in the outer side thereof with an inverted U-shaped frame 44 which
is connected with the body of the locating ring 4 for reinforcing
the structural strength of the locating ring 4. The two slide rods
5 are respectively made up of a sliding piece 50 and a sliding bar
51.
As illustrated in FIGS. 1 and 4, the gear set seat 1 of the present
invention is provided respectively in two sides thereof with a long
slot 11 and a strip hole 12, in which the sliding piece 50 and the
sliding bar 51 are received such that the sliding bar 51 reaches
one end of the strip hole 12 so as to pass through both ends of the
slot 231 of the fixing toothed sleeve 23. The end of the sliding
bar 51 is located in the ring slot 241 of the sliding toothed ring
24. As a result, when the slide rod 5 is moved back and forth in
the long slot 11 and the strip hole 12, the sliding toothed ring 24
is actuated steadily to move back and forth by the slide bar 51 in
order to allow the outer ring teeth 242 of the sliding toothed ring
24 to engage with the inner ring teeth 230 of the fixing toothed
sleeve 23. When the outer ring teeth 242 of the sliding toothed
ring 24 is engaged with the inner ring teeth 230 of the fixing
toothed sleeve 23, the pinions 214 of the gear set B 21 may be
caused to rotate within the sliding toothed ring 24 in order to
reduce the revolving speed of the hand tool. However, when the
outer ring teeth 242 of the sliding toothed ring 24 is disengaged
from the inner ring teeth 230 of the fixing toothed sleeve 23, the
pinions 214 of the gear set B 21 and the sliding toothed ring 24
are idled such that the gear set B 21 does not act to reduce the
revolving speed of the hand tool. The outer end of the slide bar 51
is located in the slanted slot 42 via the slot 41 of the locating
ring 4. When the locating ring 4 is actuated by the action ring 3,
the sliding bar 51 is caused to slide back and forth by the slanted
slot 42. When the sliding bar 51 is located at a high or low
revolving position, the outer end of each sliding bar 51 is moved
into the locating slot 43 securely.
As shown in FIGS. 5-7, the speed selecting device of the present
invention comprises a seat 6, a locating frame 7 and a push button
8. The seat 6 of an arcuate construction is provided respectively
at both ends thereof with a fitting hole 60 engageable with the
protruded piece 33 of the action ring 3. The seat 6 is provided
centrally with a hollow protruded seat 61 which is provided with a
receiving slot 62. The locating frame 7 is located over the seat 6
and is fastened to the body of the electric tool. The locating
frame 7 is provided centrally with a long hole 70 dimensioned to
receive therein the protruded seat 61. The locating frame 7 is
further provided with two retaining slots 71 corresponding in
location to each other. The push button 8 is provided therein with
a slot 80 dimensioned to receive therein the spring 81. The push
bottom 8 is further provided with two protuberances 82.
In combination, the push button 8 is disposed in the protruded seat
61 of the seat 6 such that the push button 8 is emerged from the
long hole 70 of the locating frame 7, and that the protuberances 82
of the push button 8 are located under the locating frame 7. When
the push button 8 and the protruded seat 61 are moved horizontally
to the left and the right ends of the long hole 70, the
protuberances 82 are caused to emerge from the receiving slot 62
and retained securely in the retaining slots 71. When a change in
the revolving speed of the electric tool is called for, a slight
pressure on the push button 8 can cause the protuberances 82 to
disengage the retaining slots 71. The push button 8 can be pushed
to another side where the protuberances 82 are forced by the spring
81 to move through the receiving slot 62 to be retained in another
retaining slot 71. In the meantime, the action ring 3 and the
locating ring 4 are also actuated to rotate appropriately so as to
cause the sliding bars 51 to push the sliding toothed ring 24 back
and forth until such time when the sliding bars 51 are moved
respectively into the locating slots 43 which are located
respectively at both ends of the slanted slot 42. As a result, the
speed selecting device of the present invention is capable of
causing the speed changing mechanism to operate with precision.
The change in the revolving speed of the electric tool of the
present invention is attained by the slanted slot 42 of the
locating ring 4, which is capable of actuating the slide rod 5 to
move back and forth. When the slide rod 5 is located respectively
at a high or low revolving position, the sliding bar 51 of the
slide rod 5 is moved into the locating slot 43 and is restrained by
the elastic force of the spring 32. As a result, the locating ring
4 can not be caused to turn in reverse by the reaction force which
is brought about by the electric tool operating under a great
torsional stress. The sliding toothed ring 24 can not be therefore
caused to trip so as to ensure that the speed changing operation is
carried out precisely. Furthermore, the push button 8 and the
action ring 3 of the speed selecting device can be caused by the
spring 32 to move to a low revolving position at such time when the
sliding toothed ring 24 is not engaged with the fixing toothed
sleeve 23 and when the locating ring 4 can not be actuated to turn.
Therefore, when the electric tool is started, the locating ring 4
can be located while the sliding bar 51 is restrained in the
locating slot 43 by the spring 32 without having to press
continuously the push button. It is therefore readily apparent that
the present invention has overcome the shortcomings of the prior
art.
* * * * *